Faculty

Research interests include: Jorge R. Ortiz-Zayas is a hydrologist with research interest in water management and nutrient (C, N) cycling. Projects directed by Ortiz focus on the understanding on carbon and nitrogen cycling in tropical watersheds and the restoration and management of aquatic resources. Streams and their watersheds are been heavily altered by human activities (e.g., urbanization, dams. ect.) and their biota is been impacted by overfishing and pollution. Thus, there is an urgent need to understand the functioning of stream ecosystems, how they are been impacted, and how to best manage them. Through measurements of stream metabolism and of organic carbon fluxes, Ortiz and his lab group are documenting the importance of community respiration in the carbon balance of tropical rivers. They focus on understanding natural and urban influences on nitrogen cycling in Puerto Rico in coordination with the International Nitrogen Initiative. His laboratory contributes to aquatic habitat restoration initiatives across the Island through hydrologic, physical habitat assessment, and water chemistry characterizations of streams.

Research interests include: Alonso Ramirez is a stream ecologist with interest in assessing the role of biota on stream ecosystem processes in natural and human impacted ecosystems. His research group is engaged in research in three main areas in Puerto Rico and Costa Rica: (1) Ecology of tropical streams – tropical streams are diverse and complex ecosystems that we are just beginning to understand. Our goal is to assess the functioning of tropical stream ecosystems draining forested watersheds, with particular emphasis on the role that invertebrates play in those systems. (2) Ecology of urban streams – in Latin America more people live in cities than in rural areas. Urbanization is having a tremendous impact on stream ecosystems, yet we know little about it. Our goal is to understand how streams are impacted and their responses to urbanization to best manage and protect these ecosystems. (3) Biodiversity and ecosystem function in tropical streams – Given the diversity of organisms and our lack of information on them, we are working on assessing their role on ecosystem function. In addition, we are working on generating tools to facilitate the identification of aquatic invertebrates and also their use as bioindicators.

Research interests include: Meléndez -Ackerman is an evolutionary ecologist with research interests in biodiversity conservation, biodiversity of urban systems, plant evolution and plant-animal interactions. Projects directed by her cover a wide variety of scopes and study systems. A major focus has been on biodiversity conservation and population dynamics of native species in Mona Island Reserve, a dry forest reserve between the islands of Hispaniola and Puerto Rico. A recent interest is on the study of what socio-economic factors relate to the urban biodiversity of the Rio Piedras Watershed, a major ecosystem of the San Juan Metro Areas of Puerto Rico. Melendez-Ackerman is also interested in issues related to graduate and undergraduate education and is very involved in student training projects related to the diversification of the scientific workforce. Projects led by her have been supported with funds from NSF_ ULTRA–Ex, NSF-CREST, ESAS-SEEDS, Ford Motor Co. REU, UMEB, PR-LSAMP and NSF-GK-12.

Research interests include: Zimmerman is a plant ecologist with a formation on plant reproductive ecology and evolution and current interests in Forest Dynamics and Urban Forestry. Zimmerman helps maintain and support various projects that that take advantage of long-term data and availability of the Luquillo Forest Dynamics Plot (LFPD), a 16 ha plot located in subtropical moist forest at the El Verde Field Station. The LFDP was originally established to study the long-terms impacts of hurricane disturbances, but data later showed a legacy of historic land-use in forest composition across the plot. One hypothesis addressed by Zimmerman and his collaborators using the LFPD is that human land-use would select species with particular life histories creating new forest communities with different successional pathways and distinct community equilibria after hurricanes.The LFDP is part of a coordinated network of 16 large forest plots associated to the Center for Tropical Forest Science (operated by the Smithsonian Tropical Research Institute), for the study of forest dynamics throughout the tropics. In addition to the LFPD, Zimmerman leads a project on long-term phenological responses of the LEF plant community to climate variation that is also being addressed by large scale monitoring at the El Verde Field Station. These projects are heavily funded by LTER and other NSF funds (e.g. LTREB, REU, UMEB) and have incorporated many students volunteers into research activities.

Puerto Rico provides a unique opportunity to study the interacting effects of biological and physical factors,including anthropogenic factors, on tropical marine ecosystems. My work in Puerto Rico has three main directions: (1) understanding coral calcification mechanisms by coupling neurophysiological techniques with ecology and environmental science; (2) measuring the distribution of pollutants in the watersheds of the San Juan metropolitan area and their impacts on local flora and fauna; and (3) use of macroalgal biomass for the production of biofuels and bioproducts and contaminant bioremediation. These three areas require a highly interdisciplinary approach and will provide critical information for predicting coastal ecosystem trajectories as disturbances from human encroachment and storm activity increase in the region.

Research interests include: Mei Yu is a landscape ecologist with interests in spatial statistics, and modeling applications in terrestrial ecosystems at multiple spatial and temporal scales, species distribution modeling; biodiversity analysis and ecosystem mapping. One project in the sandy grasslands of Maowusu, China has addressed the role of runoff (including subsurface drainage flow) in decisions related to the type of vegetation management designed to combat desertification by reducing soil erosion.

Research interests include: Brokaw and collaborators maintain and support various projects that that take advantage of long-term data and availability of the Luquillo Forest Dynamics Plot (LFPD) a 16 ha plot located in a subtropical moist forest at the El Verde Field Station. Brokaw and Zimmerman lead The Canopy Trimming Experiment (CTE), a large scale (spatial and temporal) manipulation of the canopy at the Luquillo Mountains that simulates increases in hurricane frequencies to determine its impacts on forest biodiversity and ecosystem function. Brokaw is also studying the effects of land use by the ancient Maya on present-day forests in Mesoamerica. These projects are heavily funded by LTER and other NSF funds (e.g. LTREB, REU, UMEB) and have incorporated many students volunteers into research activities

Research interests include: Mayol-Bracero is a chemist with interests in studying variability of atmospheric aerosols and their impact on clouds, precipitation, and climate. Air particles of natural and anthropogenic origins can have important consequences on climate, ecosystem function, degradation of structures, and human health. Mayol-Bracero has special interest on African dust particles since each year these particles are carried by the trade winds from the North African desert to the Caribbean, particularly during the summer months. Projects led by Mayol-Bracero address questions such as what are the physical and chemical properties of aerosol particles as a function of their origin (African dust, North America continent, maritime trade winds, Southeastern Caribbean wind currents) and after long-range transport. One hypothesis is that incoming African dust into the Caribbean may have significant effects on cloud radiative properties and seasonal rain patterns of Tropical Montane Cloud Forests of the Luquillo Mountains, Puerto Rico. Collaborative work is done with institutions such as Scripps, UCSD, University of Paris East (LISA), Max Planck Institute for Chemistry in Mainz-Germany, University of Colorado, Colorado State University, UNAM-Mexico, the ETH (Switzerland), University of New Hampshire, the IITF, and the Institute for Tropospheric Research in Leipzig-Germany. Funds for this area have been generated primarily through NSF (ATM, AGS, EPSCOR, LTER, CREST, NSF-ATM, PRLSAMP, UMEB) and Institutional Funds from UPR.

Research interests include: (1) Multiscale ecosystem modeling, (2) Modeling of ecosystem adaptation to environmental changes, and (3) Coupling ecosystem processes with changes in anthropogentic activities such as land use changes.

Research interests include: Zou has research interests that address the function of soil ecosystems and is a collaborator on UPR’s China Initiative, a project from the UPR System President’s Office that aims to create formal mechanisms for educational and research exchange between UPR and the University of Beijing. Ongoing focuses of Zou’s research are the factors that regulate global soil CO2 efflux. How this phenomenon may be impacted as a function impending changes in climate change remains highly uncertain and require studies on the role of biotic factors in soil respiration. Current research is being conducted by Zou and collaborators in tropical forests of China and Puerto Rico addressing the role of root function (root exudates) and litter inputs on soil respiration as well as the interaction of forest liter and soil biota on soil ecosystem function. On a more applied scope, Zou has also been studying the influence of exotic vegetation on the biomass and abundance of soil fauna of tropical forests. One hypothesis is that differences in nutritional values among plant species may lead to related changes in biomass and abundance of soil macrofacuna. Results by his students suggest that different plantation species could lead to different ecosystem responses in terms of the regulation of biomass and abundance of millipedes in degraded tropical lands. Funding for this researcher has included NSF-LTER, REU, UMEB and the Chinese Academy of Sciences.